The present invention relates to a portable power tool with a percussion mechanism, particularly for use with chiseling tools.
A percussion mechanism has multiple moved components that move repeatedly along a working axis and strike each other. This results in considerable noise generation. Precise guiding of the striking components parallel to the working axis prevents diagonal skewing of the striking components and rattling due to a partially radial movement.
The portable power tool according to the invention has a tool holder, in which a tool can be movably inserted on a working axis in a striking direction. A percussion mechanism has a striker coupled via a pneumatic chamber to an exciter moved periodically along the working axis and an intermediate striker arranged in the striking direction downstream from the striker. The intermediate striker is guided in a slide bearing with a tolerance coaxially to the working axis. The intermediate striker has a ring-shaped bead. A hollow cylindrical backstop is arranged in the striking direction upstream from the bead. The backstop is moveably guided on a sliding surface with radial play along the working axis. The radial play is at least three times as large as a tolerance of the guide of the intermediate striker in the slide bearing. The striking components are rigidly guided as is normal. In contrast to this, it may prove to be advantageous to not rigidly guide a backstop for the intermediate striker. Even though it can now move radially and thereby rattle, the entire noise generation is less. The impact of the intermediate striker induces a radial vibration in the backstop, which also depends on the guide. The rigid guide hereby proves to be more unfavorable since the resulting higher frequencies stimulate the housing in a resonant manner.
A design provides that the mass of the backstop amounts to between 20% and 40% of the mass of the intermediate striker. The backstop may be supported on a damping element opposite the striking direction. In particular, the backstop may be inserted in a pre-tensioned manner between the damping element and an additional damping element arranged in the striking direction.
A design provides that a spring element encompasses a radial external surface of the backstop. The spring element centers the backstop to the working axis after an impact of the intermediate striker has occurred.